Method for temporary protection of ships after launching

ABSTRACT

A METHOD IS DESCRIBED FOR TEMPORARY PROTECTION OF SHIPS AFTER LAUNCHING; IN ACCORDANCE WITH THE METHOD, A COVERING WAX COATING IS APPLIED ON TOP OF THE USUAL COATING ON THE SHIP HULL, THE SAID LAYER BEING WORN OFF WHEN THE SHIP IS PUT INTO GENERAL SERVICE.

United States Patent 351/ 1 Int. Cl. B44d 1/34; B63b 9/00 Us. or. 117-6 3 Claims ABSTRACT OF THE DISCLOSURE A method is described for temporary protection of ships after launching; in accordance with the method, a covering wax coating is applied on top of the usual coating on the ship hull, the said layer being worn off when the ship is put into general service.

The present invention relates to a method for temporary or provisional protection of ships after launching. The invention is thereby intended to give a provisional protection both against corrosion and fouling, and is particularly intended for use during the period of construction of the ship after launching, when the ship is stationed at the outfitting quai.

In the ship-building, the ship was previously finished in dry dock, whereafter the necessary underwater coating was applied and it was launched. The necessary outfitting of the ship including installation of engine etc. was then carried out and the ship dry-docked once more, cleaned and the final paint applied, whereafter the ship was delivered to the shipowner. With the recent increase in the size of ships, problems arise with regard to the last docking prior to delivery, since in only a few places in the world are there docks large enough for such ships. The dock where the ship was built would already be in use with a new construction. In such large ships, the period of outfitting is significantly greater, perhaps up to three to five months, while the ship is stationary at the quai. This means that the paint coatings are already subject to action both by the sea water and by organisms and impurities in the sea water with a result that the toxic substances in any antifouling coating are washed out, and a corrosion process may already have begun, the ships bottom being already somewhat roughened and fouled prior to delivery. The ship must then be taken up for cleaning at an earlier date than is desirable, entailing substantial cost.

The object of the present invention is to eliminate this great disadvantage occurring in present day construction of ships, which must to a great extent be delivered in a somewhat roughened and possibly fouled state.

In accordance with the invention, this is achieved in that the coatings intended for sea-going service are applied to the ship prior to launching, whereafter a covering wax coating is applied to the entire underwater surface, the said wax coating being worn away when the ship is put into general service. In accordance with a further feature of the invention, a paraffin wax is used.

The advantage achieved by means of the method according to the invention is thus that when the hull of the ship is finished, all the coatings intended for normal operations together with anti-fouling can be applied so that the underwater surface is ready for delivery. On top of this, a wax layer is applied which protects the coatings applied and covers them, that is to say conserves them, and the wax layer gives simultaneously a temporary protection during the outfitting period. The effect of a parafiin wax is that it gives, without additives, a certain anti-fouling effect whilst at the same time it obviously protects corrosion also. On application the wax has an adhesive quality to the surface sutficient to give protection for a certain period of time. At the same time the adhesive quality, on normal operation of the ship, that is to say when the ship sails at a fair speed, is such that the wax coating will wear off in a comparatively short time. Thus, even after a very short period of time, the wax coating is worn from the underwater surface of the ship and the anti-fouling coatings intended for normal operation are freed for full effect, so that the underwater surface can be said to be in newly painted" condition on delivery.

Even though a certain fouling of the wax coating should occur after a certain period of time, this will be attached to the outer coating only and will be worn off together with the coating on passage.

The wax coating is applied preferably in a thickness of about 1 mm. In order to give an even better protection during the outfitting period, the use of the wax coating may be combined with a curtain of air released around the hull of the ship.

By means of the invention, a temporary protection of the ship hull is achieved during the last part of the construction period by application of an extra layer, the said layer disappearing of itself when the ship is in normal operation, so that no extra work is necessary for removal of the temporary protection. It is emphasized that the advantages of the invention are also applicable after each launching, that is to say also on older ships which have been in dry dock.

For the sake of completeness, it is noted that from French Pat. No. 1,496,214 it is known to apply the antifouling coating adhered to a carrying sheet of, for example, kraft. A water soluble glue is used as adhesive. In the patent, it is disclosed that the carrying sheet quickly loosens, whereafter the anti-fouling coating is revealed, it is clear, however, that it is possible to achieve a more rapid or slower dissolution by varying the degree of water solubility.

A technique related to that of the invention, in which wax is used as temporary protection in ship building, is known from German Pat. No. 1,227,592. In this case, however, the wax coating serves another purpose, since it is applied directly to the steel section before the bottom of the ship is treated with anti-fouling agent.

Having described our invention, we claim:

1. A method for temporary protection of an underwater surface of a ship after launching, comprising:

applying to the underwater surface of the ship a coating of paint intended for normal operation, applying a temporary cover coating consisting essentially of a wax containing no additives to the coating of paint on the underwater surface of the ship to thereby provide both fouling and corrosion protection for the underwater surface of the ship and moving the ship through water at a speed sufiicient to 3 4 wear away the wax coating so as to expose the coat- 3,202,523 8/1965 Steeg 117-6 X ing of paint in a newly painted condition. 2,489,228 11/ 1949 Rudd 117-435 X a grgifil'lllleglaiflil according to claim 1 wherem the wax 1s FOREIGN PATENTS 3. A method according to claim 1 wherein the thick- 5 9 10/1966 Germany 1176 11 f th x coatin abo t 1 mm.

6 wa g u RALPH HUSACK, Primary Examiner References Cited U.S. Cl. X.R.

UNITED STATES PATENTS 98,862 1/ 1870 Gardner et a1 117-168 X 1 2,838,419 6/1958 Francis 117135 X 

